Obesity “is not a choice. Neither is it a lifestyle habit.” Higher body weight isn’t a result of laziness or inadequate willpower. Rather, it is due to unconscious neural processes at work. Ultimately, the brain is the one in control.
Genetic elements may account for 50-75% of the differences in body mass index (BMI) within the population.
A group of researchers from Université Laval and the Quebec Heart and Lung Institute Research Centre examined the genomes of over 800,000 individuals of European ancestry, pinpointing 60 distinct proteins found in the brain that could serve as crucial body weight regulators.
The research delved into the connection between genetic areas related to body weight and the proteins present in the brain.
Several studies have indicated that numerous genetic regions impact body weight. However, the function of these genes is largely unknown.
The findings of this study, published in iScience, revealed “that about 60 of these genes encode proteins that could influence body weight via their expression in the brain,” according to first author Éloi Gagnon.
In this study, researchers concentrated on a specific brain area that may affect the sensitivity to food rewards, like the enjoyment experienced when consuming high-fat or sugary foods, as well as cognitive functions such as decision-making and memory. The dorsolateral prefrontal cortex, the region in focus, is also believed to be involved in appetite and the feeling of fullness.
The team’s findings are in line with the theory that the brain is a key element in controlling body weight. This finding could help to explain why people’s BMIs vary so greatly.
Benoît Arsenault, the study’s lead author, professor at the Université Laval Faculty of Medicine, and researcher at the Quebec Heart and Lung Institute, highlights that numerous misconceptions persist in the public sphere concerning the influence of genetic factors on body weight. He often encounters the argument that genes cannot account for the rise in the population’s average weight over the last 40 years since our genes have remained unchanged.
The researchers suggest that the changing food landscape over recent decades may have impacted eating habits and the body’s ability to store energy.
“Individuals with a genetic predisposition to an elevated body weight,” according to prof Arsenault, “have a higher weight than before, whereas individuals who do not have this predisposition were thin before and are still thin today.”
The team thinks that the biological function of these proteins in diverse areas of the brain and their significance to energy homeostasis, i.e. the balance between food intake and energy expenditure, need more investigation.
Overall, our study’s findings suggest that the changing dietary environment and the proteome of the brain may interact. This connection may affect how people eat and how much energy they store.
The author emphasizes that individuals with larger body sizes frequently face biases and may encounter discrimination, bullying, or stigmatization. These issues, related to fatphobia, can have negative effects on both physical and mental health. The researcher also points out that numerous studies have demonstrated that factors beyond our control, including genetics, contribute significantly to the variation in body weight across the population.
“Weight is not a choice. Neither is it a lifestyle habit,” comments Benoît Arsenault.
Higher body weight isn’t a result of laziness or inadequate willpower. Rather, it is due to unconscious neural processes at work.
“The brain is the one in charge.”
The team hopes “that the results of this study can partly explain why body weight varies so much from one person to another.”
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